分枝列当种子萌芽生物学特性

以寄生于番茄的分枝列当种子为试验材料,研究预培养阶段温度、时间、渗透势以及培养阶段温度、萌发刺激物(独月却金内酯类似物GR24)的浓度和渗透势对种子萌发的影响,以期找到种子萌发的最适条件,从而可以人为创造控制分枝列当生长的环境,以达到有效防治的目的。结果表明:预培养阶段的最适培养温度为25℃,最适培养时间为6 d,最适的渗透势为0 MPa;培养阶段的最适培养温度为25℃,最适GR24浓度为1μmol/L,最适的渗透势为-1 MPa。     

陕西苹果树腐烂病菌(Cytospora spp.)不同分离株的生物学特性与致病性研究

 本研究从陕西分离得到61株苹果树腐烂病菌(Cytospora spp.),选取在PDA培养基上菌落特征差异明显的7个分离株,对其生物学特性及致病性进行研究。结果表明:各分离株在PDA、PSA、PMA和PEMA培养基上菌落生长较好,但在PDA上的菌落颜色和产孢情况差异很大。各分离株均能在5~32℃生长,但对35℃以上高温的适应性差异较大;所有分离株均能在pH4~9的条件下生长,最适pH为5~6;光照对各分离株的菌落生长有明显的促进作用。各分离株均可在Cza-pek培养基及供试的其它碳、氮源培养基上生长,其中以葡萄糖、麦芽糖和酵母膏为最佳碳、氮源。采用烫伤接种的方法,分别以菌饼和分生孢子悬浮液接种苹果离体枝条,两者均可侵染发病,但各分离株致病力差异显著,其中菌落颜色为黄褐色的菌株致病性强。因此,根据菌落颜色、致病性和生物学特性可将这7个分离株划分为3个类群:Ⅰ型为黄褐色强致病类群,但各分离株的产孢量有差异;Ⅱ型为乳白色不产孢的弱致病类群;Ⅲ型为灰褐色易产孢弱致病类群。其余54株分离物均属于Ⅰ型,这些结果说明陕西省苹果树腐烂病菌具有多样性和致病性分化现象。     

DNA条形码、形态学与地理分布相结合的植物果实(种子)鉴定方法——以口岸截获的外来入侵植物犬蔷薇(Rosa canina L.)为例

以单一方法鉴定物种具有参考文献(或比对数据)少、专业要求高的缺点。以新疆口岸进境货车截获的未知植物果实为例,从分子、形态、地理分布3个维度,对该未知果实逐级进行分类鉴定。根据ITS、atp F-H、psb K-I 3段植物DNA通用条形码序列,以及形态学和地理分布信息,最终确定该未知果实为原产于西亚的蔷薇科蔷薇属犬蔷薇(Rosa canina L.)。本方法简单、准确,弥补了现有单一检测鉴定技术的不足,适用于进境产品中植物果实或种子的检疫鉴定。     

Revisiting strategies for reducing the seedbank of Orobanche and Phelipanche spp.

Weedy Orobanche and Phelipanche species are important in Southern and Eastern Europe, the Middle East and North Africa, and have recently been reported in the USA, Australia and some countries in South America. Rather than being controlled, the Orobanche and Phelipanche problem is increasing, both in intensity and in acreage. Large areas of new territory are at risk of invasion, if care is not immediately taken to limit the introduction of parasitic seeds and to educate farmers and others to be alert for new infestations. There is an urgent need to re-evaluate novel integrated Orobanche and Phelipanche management programmes that will allow a better control of the parasite species and limit their distribution. The main obstacle in the long-term management of Orobanche and Phelipanche infested fields is the durable seedbank, which may remain viable for decades in the field. Large quantities of long-lived seeds give the parasite genetic adaptability to changes in host resistance and cultural practices. As long as the seedbank is not controlled, the need to control the parasite will persist whenever a susceptible host is grown in the infested field. We discuss strategies for seedbank reduction, paying particular attention to cultural practices, whereas chemical and biological control methods are covered by other reviews in this issue.     

Broomrape (Orobanche spp.) control with ethylene dibromide and chloropicrin

Ethylene dibromide effectively controlled Orobanche crenata Forsk. and O. cernua Loefl. but was not effective against O. aegyptiaca Pers. and O. mutelii F. Schultz. Chloropicrin was considerably less effective than ethylene dibromide. Mixtures of both compounds did not result in improved broomrape control but nonetheless had a positive effect on crop yield. Destruction des Orobanches avec du dibromure d'ethylène et de la chloropicrine Le dibromure d'éthylène a été efficace contre Orobanche crenata Forsk et O. Cernua Loefl, mais non efficace contre O. aegyptiaca Pers, et O. mutelii F. Schultz. La chloropicrine est beaucoup moins efficace que le dibromure d'ethylène. Les mélanges des deux matières actives n'ont pas amélioré l'efficacité sur orobanches mais néanmoins ont eu un effet positif sur le rendement de la culture. Bekämpfung von Orobanche-Arten mit Ethylendi-bromid und Chlorpikrin Mit Ethylendibromid konnten Orobanche crenata Forsk. und O. cernua Loefl., aber nicht O. aegyptica Pers. und O. mutelii F. Schultz bekämpft werden. Chlorpikrin war beträchtlich weniger wirksam. Mischungen der beiden Wirkstoffe ergaben keine bessere Wirkung, beeinflussten aber den Ertrag der Kulturpflanzen positiv.     

Comparative proteomic analysis of Orobanche and Phelipanche species inferred from seed proteins

Orobanche and Phelipanche species are root parasitic plants some of which infect important crops, causing extensive damage. In an attempt to unravel molecular systematic in these genera using protein markers, we established the protein profile of twelve species by two-dimensional gel electrophoresis (2-DE). Proteins were detected by Sypro Ruby staining and the gel images were digitalised and analysed. The 2-DE maps contained from 30 to 140 protein spots for the analysed species. A virtual master gel was built with spots present in all species and revealing the presence of 260 protein spots. Only one protein was monomorphic, while 143 were unique to a single species. Proteins were scored for the presence or absence of homologous spots to create a binary matrix. Phylogenetic analysis was carried out using maximum parsimony and distance method. The trees obtained were rooted using Cistanche phelypaea as an out-group. Both analyses showed Orobanche as a monophyletic group. AMOVA analysis revealed phenotypic diversity between species within genera, as well as a considerable level of variation between genera. This is a first step to help in the phylogenetic classification of parasitic plants by means of proteomics.     

Seed viability determination in parasitic broomrapes (Orobanche and Phelipanche) using fluorescein diacetate staining

Fluorescein diacetate (FDA) was investigated as a potential viability stain for seeds of holoparasitic broomrapes Orobanche and Phelipanche (Orobanchaceae), using four weedy and two non-weedy taxa. FDA viabilities were compared with the currently used 2,3,5-triphenyl tetrazolium chloride (TTC) test, and in vitro germination induced by the strigolactone analogue GR-24. Viable FDA-stained seeds were characterised by bright yellow–green fluorescence under 450–490 nm blue light. These viable seeds could be discriminated from non-viable seeds, in which low levels of fluorescence, similar to non-stained control seeds were observed. FDA viabilities were not significantly different from those obtained using the TTC stain; however, viability values for both stains were consistently higher than levels of artificially induced germination. Positive TTC-staining showed continuous variation that was difficult to interpret. Nevertheless, the TTC test does not involve grinding seeds, and therefore probably remains a practical alternative to FDA for screening soil samples contaminated with Orobanche and Phelipanche seeds, which indicates different applications for the two viability tests. Interestingly, the strigolactone analogue GR-24 only induced germination in O. crenata , P. ramosa and O. minor , suggesting a high specificity towards this germination inducer among the species investigated. We suggest that FDA-staining provides a potential alternative to the currently used TTC test for seed viability assays for Orobanche and Phelipanche , and other parasitic weeds which are an obstacle to crop cultivation.     

列当杂草及其防除措施展望

根寄生杂草列当Orobanche spp.每株可产生大量细小的种子,易于传播,且在出苗前已经对寄主作物造成危害,使列当的防除成为一个世界性难题。本文详述了列当的生活史、为害现状以及防除措施,并突出了生物防除的生态效益与经济效益。基于＂诱捕＂作物及＂捕获＂作物诱导列当种子＂自杀发芽＂理论的防除机制,本文提出了新型可持续生态防除思想,为列当科杂草防除提供参考。     

Orobanche crenata resistance and avoidance in pea (Pisum spp.) operate at different developmental stages of the parasite

Orobanche crenata (broomrape) is an important constraint to pea (Pisum sativum) cultivation in the Mediterranean area, because little resistance is available in commercial crop varieties. Field experiments have demonstrated that some resistance is present in a number of P. sativum and P. fulvum accessions. The goal of this work was to characterize such resistance. The Pisum–O. crenata interaction and the resistance symptoms were studied under controlled conditions by using Petri dish and polyethylene bag assays. The content of phenolics and peroxidase activity in host tissue from infected and non-infected plants were also measured. Resistance and avoidance mechanisms, acting at different developmental stages of the parasite, have been identified, including low stimulation of O. crenata seed germination, unsuccessful penetration of host roots, delay in post-attachment tubercle development and necrosis of the attached tubercles. Infection caused an increase in the content of total soluble phenolics in some Pisum genotypes. Peroxidase activity was higher in resistant than in susceptible accessions. Results obtained with different Pisum genotypes showed that resistance is the result of several mechanisms acting at different stages of the infection process. Resistance is also related to increased levels of peroxidase activity in host roots.     

室内条件下向日葵列当和弯管列当在三种不同寄主上寄生能力的比较

以向日葵列当Orobanche cumana Wallr.和弯管列当O.cernua Loefl.为研究对象,利用已有的室内寄生体系来研究两种列当在向日葵、烟草、番茄3种寄主上的寄生能力。结果表明,向日葵列当在室内条件下不仅能够寄生在向日葵上,同时也可以在烟草与番茄上寄生;但其寄生效率在上述不同的寄主之间存在显著差异,而在相同寄主的不同品系间没有差异。交互侵染的结果表明,在寄主番茄上,弯管列当平均每株寄生的瘤结数量为16.3个,向日葵列当只有2.5个;在寄主向日葵上,向日葵列当的平均寄生瘤结数量为25.2个,弯管列当为27.6个,预示着弯管列当在番茄上寄生效率均显著高于向日葵列当,而在寄主向日葵上,二者寄生效率差异不显著,均能高效寄生在向日葵根系上。上述研究结果将为向日葵列当和弯管列当发生严重地区作物轮作对象的选择提供理论依据。     

我国新疆焉耆垦区作物轮作种植模式防除列当的有效性研究

本研究以新疆地区危害最严重的向日葵列当和瓜列当为研究对象,通过室内水培试验和室外盆栽模拟轮作试验来探究焉耆垦区轮作模式对两种列当的防除效果。结果表明,室内水培试验中各轮作作物的根系分泌物及萃取相刺激瓜列当种子的萌发率均在20.0%以下,但刺激向日葵列当种子产生的萌发率达到了50.0%以上;室外盆栽模拟轮作试验中,甜菜、小麦、辣椒与加工番茄轮作后,瓜列当的寄生数量未显著降低;但与向日葵轮作后,向日葵列当的寄生数量显著减少了60.0%以上。不同品种甜菜、辣椒和小麦地上部甲醇提取液刺激瓜列当种子的萌发率均低于10.0%,但是刺激向日葵列当种子的萌发率均达70.0%以上。本研究表明新疆焉耆垦区轮作种植模式不能有效防除瓜列当,但模式中的轮作作物均能够有效防除向日葵列当。本研究结果为防除新疆焉耆垦区向日葵列当和瓜列当提供理论依据。     

烟草及向日葵上列当Orobanche cumana的发生及其生物防治

 近年,在河北省部分烟草和向日葵种植地发现大量寄生性杂草列当发生并造成严重为害。经鉴定为向日葵列当Orobanche cumana Wallr.。向日葵、烟草、番茄和黄瓜等作物的根分泌物能够刺激向日葵列当O. cumana种子萌发,而油葵根的分泌物则不能刺激向日葵列当种子萌发。利用列当致病镰刀菌L2菌株进行田间生物防治,防治效果达到92.4%。L2菌株对小麦、玉米、棉花、烟草和向日葵等作物生长无影响,L2菌株粗毒素能够抑制列当种子萌发,并造成列当种子萌芽管损伤。